A 68-year-old man presents to his cardiologist’s office for chest
discomfort while training for a marathon. He is very active and has run one or
two marathons each year. He does not
have high blood pressure, diabetes or elevated cholesterol levels. He is not
obese and does not smoke. However, his father had a heart attack at age 40 and
a brother had a heart attack and heart surgery in his 40’s. He underwent an exercise stress test followed
by a heart catheterization, which showed severe blockage in his heart arteries.
He then had coronary artery bypass
surgery. At his follow up visit after his bypass, he asks, “Why did this happen
to me? I have done everything right for so long”.
What factors contribute to the development of heart artery
disease? Is it our genes, how we are built? Or is it our lifestyle? It’s the age-old question of nature versus
nurture. It has been known for years
that heart artery disease runs in families.
This is especially true for families with members who had heart attacks
at young ages (generally less than 50 years old). It has also been known for years that certain
lifestyles contribute to heart artery disease. Smoking, obesity, diet, and a
sedentary lifestyle have all been associated with the development of blockage
in the heart arteries. It is also known that
lifestyle modification can control or even reverse heart artery disease. In the
1990’s Dr. Dean Ornish developed an intensive lifestyle modification program
focusing on a plant based diet, smoking cessation, moderate exercise and stress
management. He found that lifestyle changes were as good as heart procedures
(angioplasty or bypass surgery) in reducing chest pain without increasing heart
attacks or deaths. So, which is more
important, genes or lifestyle?
A recent study involving 55,000 participants sought to
define the interplay between genes and lifestyle on the development of heart
artery disease. Based on DNA analysis,
the participants were placed into two categories, high genetic risk for heart
disease or low genetic risk. Similarly,
the participants were placed into two lifestyle categories, a favorable
lifestyle (at least three of four healthy lifestyle factors) or an unfavorable
lifestyle (no or one healthy lifestyle factor).
The healthy lifestyle factors were: no smoking, no obesity, regular
physical activity and a healthy diet. The researchers found that genetic risk
and lifestyle factors independently contribute to heart artery disease. In other
words, having a high genetic risk or an unfavorable lifestyle is equally risky
in developing heart disease. Both nature and nurture matter. The researchers also
found that genes were not the final determinant in heart disease. In the high
genetic risk category, those who followed a favorable lifestyle had a nearly 50%
reduction in risk of heart disease compared to those who followed an
unfavorable lifestyle. Therefore, following a favorable lifestyle can reduce
genetic risk.
The long distance running of our 68-year-old man could not keep
him from meeting the cardiac surgeon; his family history eventually caught up
to him. However, if he had not been as active and had followed an unfavorable
lifestyle, he very likely would have manifested heart artery disease at a much
earlier age, similar to his father and brother.
By following a favorable lifestyle, he had delayed the progression of
his heart disease, likely by about twenty years. So, clearly you cannot out run your genes. On
the other hand, your genes don’t necessarily determine the fate of your heart.
If you have a strong family history of early heart attacks, don’t give up, sit
on the couch and not take care of yourself.
Lifestyle changes make a difference, although they are not easy.
Following a favorable lifestyle is an every day, all the time, year after year
commitment. It is, however, worth it, especially for those at the highest
genetic risk for heart disease.
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